Health experts say the meat could contain a strain of E. coli that worries them most.

CLEVELAND -- A massive ground beef recall is causing concern just days before the holiday weekend.

Health experts say the meat could contain E. coli. They say it's the type of strain that worries them the most.

"It can release a toxin into the blood that attacks the kidneys and frequently can cause life-threatening illnesses for young children," said Caroline Smith with the Center for Science in the Public Interest.

Already 11 people have been sickened in four states -- Michigan, Missouri, Ohio and Massachusetts.